Drilling safety joint



July 28, 1936.

E.. BURNS ET AL DRILLING SAFETY JOINT Filed June v17, 1935 ATTORNEY Patented July 28, 1936 PATENT OFFICE nnmmG SAFETY Jom'r Erwin Burns and Harry P. Wickersham, Los Angeles, Calif., assignors of one-third to Lawrence P. Baash, Los Angeles, Calif.

Application June 17, 1935, 4Serial No. 26,890

Claims. (Cl. Z55-28) This invention relates to well drilling tools and particularly pertains to a drilling safety joint.

In the drilling of oil wells itv sometimes occurs that a lower length of drill string and the tool f5 carried thereby may become fastened accidentally within the well. Under such conditions it is necessary to attempt to dislodge the fastened members and when this is not possible to thereafter attempt to disconnect a portion of the drill l0 string-so that the unscrewed length of drill pipe may be recovered. In the event that an attempt is made to unscrew the drill string at some joint in its length or to rotate' the drill string in a counterclockwise direction the drill string will separate at the coupling which offers the .least resistance yto an unscrewing motion.4 It will be recognized that such an operation is not satisfactory since the length of drill string removed will be determined by accident rather than in- 2o a predetermined manner. It is common practice therefore to provide a jointed connection at a predetermined point in the length of the drill string which connection will hold the drill string assembled when rotating in a clockwise direction, but which will release and allow separation of the drill string at that point to take place when rotated in a counterclockwise direction. Such devices are commonly called safety joints. These 3 joint, the parts of which are normally Elocked against separation by rotation in either direction, y

and which joint may be optionally controlled by manipulation of the drill stringto release its parts from positive engagement and to permit counter rotation of the upper end of the drill string to separate the locking parts of the joint.

The present invention contemplates the provsion of two tubular sections interposed in the line of a drill string, and which sections interlock with each other through an intermediate member splined to oneof the sections and threaded to the other, ysaid tubular sections having a positive locking connection holding the sections against relative rotation in either direction, and one of '50 said tubular sections having a positivedriving V 'Figure 1 is a fragmentary view in elevation showing a section of drill string with the safety joint of the present invention interposed between lengths thereof.

Fig. 2 is an enlarged view in longitudinal section-and elevation with parts broken away to 5 disclose the operative elements of the safety joint with which the present invention is concerned.

Fig. `3 is a view in transverse section through the safety joint as seen on the line 3 3 of Fig. 2, and shows the splined connection between the 10 interconnecting member and one of the tubular members, as well as indicates the relative position of the positive locking means.

Fig. 4 is a view in transverse section as seen on the line 4-4 of Fig. 2 and as showing the 15 interrupted thread.

Referring more particularly to the drawing I0 indicates an upper section of drill string. II indicates a lower section of drill string, the upper section being provided with a coupling I2, which 20 is connected with a sub I3 carried at the upper -end of a safety joint structure generally indicated at I4. A coupling I5 connects the lower drill string section II and the safety joint. The safety joint I4 comprises three major elements, 25 an upper tubular section I6, a lower tubular section I1, and an interconnecting section I8.

"Ihe upper tubular section is internally threaded structures for the most part will not permit a a. main central bore I9 terminating intermediate 30 the length of the vtubularsection by a shoulder 20 from which a bore 2| of reduced section continues through the upper tubular member. Extending downwardly from opposite sides of the upper tubular member I6 and projecting from the lower 35 edge thereof are a pair of J-shaped hooks 22 which have longitudinally extending leg portions 23, a laterally extending portion 24, and an upturned hooked end 25. 'Ihese members project from the bottom of the upper tubular mem- 40 ber I6 and extend into recesses 2B which are formed in the circumferential side face of the lowertubular member II. These recesses have an entering throat of a width in excess of the overau width of the J hooks 22, and m the upper 4 wall of each of the recesses is a downwardly extending lug 21 around which the hooked end 25 of a hook 22 extends, and by which it is engaged.

'I'he depth -of the recess 26 is such as to permit lower tubular member from their positive en- 55 are in positive engagement with the lug 2'I carried upon the lower tubular member II a space will occur between the contiguous ends of the two tubular members.

This space is partially occupied by a collar 28 formed around .the body of the interconnecting member I8 at a point intermediate its ends.

collar 28 is formed with inclined faces 29 ter- The under face of the minating in longitudinally disposed 'shoulders 30 While similar faces` and shoulders 29' and 30' are formed on the upper end of the lower tubular member I1. The inclination of the fa'ces 29'and l 29' are sordisposed as to cause the shoulders to insure an initiatory rotation of theupper tubular member I6 and the lower tubular member I'I' to accommodate .the longitudinally 'extending portions 23 of the hooks 22. This will tend to vprevent relative rotation between the upper tubular member I6 Yand the interconnecting member- I8, although additional means are provided for this purpose which includes splines 32 which connect the upper extending portion of the member I8 with the upper tubular member I6, for positivel rotation and longitudinal sliding movement. ing member I8 is cylindrical and tubular, having a central fluid circulating passageway 33 therethrough. Carried at the upper end of the member I8 is a packing nut 34 around the body of which suitable packing material 35 is placed to form a fluid seal between the wall of the 'bore I9 in the upper tubular member I6 and the interconnecting member I 8. By this means the upper tubular member I6 may reciprocate upon Y the upper end of the interconnecting member I8 adistance as represented by the space 35' between the lower face of the tubular member I6 and the upper face of .the collar 28. The downward movement of the interconnecting member I8 with relation to the tubular member I6 is limited by engagement of the nut 34'with the shoulder 20 within the member I6. Normally the nut 34 is held in this seated position by the expansive action of aoil spring 36which is interposed be- ,.tween the end face. of the nut 34 and the end face of sub I3; The end portion of the interconnecting member I8 which occurs below the collar 28 is cylindrical and is formed with a continuation of the central iluid circulating passageway 33. The lower end of the passageway 33 is vformed with an enlarged counterbore 3'I which receives a wash'pipe 38 threaded into the end of the lower tubular member II and communicating with a downwardly extending fluid passageway 39. This wash pipe ts the counterbore 3.1 with a sliding lit and is further packed with a packing 48 held by a packing gland 4I to prevent leakage of fluid into the safety joint and therethrough.

Thelower tubular member I'I is formed with mutilated thread secinons 42 which are arranged lengthwise within bore 43 of the lower, tubular section I'I. Complementary mutilated thread sections 44 are formed lengthwise of the outer cylindrical face of the interconnecting member I8. Spaces v45 will occur between the ends of the threaded members as shown in Fig. 4 of the drawingso that when the interconnecting member is turned aquarter of a turn the thread sections --42 and 44 will move from theirl meshing positionsl in lockedA relation to -the lug 2'I.

The upper end of the interconnectgagement with each other. When the hooks 22 interconnecting section to bodily move lengthwise as the parts of the safety joint are released and separated.

In operation of the present invention the safety joint is assembled as shown particularly in Figs. l and 2 of the drawing. Here it will be seen that normally the J-shaped hooks 22 will fit within the recesses 26 with the hooked ends 25` of the members 22 positively hooked over and engaging the lug 2'I in the recesses. Thus the tubular members will be held by the members 22 and 2`I in a lockedposition since expansion spring 36 will exert a force tending to separate the two tubular elements and keep the hooks 22 At the same time the threads 42 of the lower tubular member and the threads 44 carried by the interconnecting member will be in mesh to hold the lower tubular member Il and the interconnecting member I8 in positive connection with each other. 20 In the event that the portion of the drill string A occurring below the safety joint or the tools carried thereby should become fastened in the well .reverse rotation may be imparted to the safety joint and the lower section of the drill string due 25 to the fact that the J-hooks 22 positively engage the lug 2I of the recesses 26. It will be understood that during this operation at least part of theA weight of the drillstring is being supported from the derrick. When, however, it is desired 30 to disconnect the J-hooks 22 from the members 2'I the weight ofthe drill string is released from its support, or at least sufficiently released, so that it will overcome the expansive action of spring 36 and allow the member 25 of each of the 35, hooks 22 to clear the lugs 2l; after which the upper tubular member I6 and the interconnecting member I8 may be rotated in a counterclockwise direction so that the shoulders 30 and end 25 of thel J-hooks 22 have moved to a position of clearance with relation to the lugs 21 the threads 42 and 44 will be out of engagement and it will be possible to directly raise the upper drill string section with the upper tubular mandrel and the interconnecting member I8.

It will thus be seen that by the structure here shown it is possible to temporarily connect sections of drillstring in a manner to insure that said sections may be positively rotated'in unison in clockwise and counterclockwise directions, and that by manipulation of the upper end of the drill string it will be possible to quickly release the safety joint sections and remove the upper drill string section with its associated safety joint parts.

In order to facilitate in the assembly of the members I6 and I'I and the lock hook 22 with the lug 2'I, it may be desirable to'cut recesses 28'- in the shoulder 28. These recesses will, of course, 60 be wideV enough to laccommodatethe hooks 22 at their widest parts.

While we have shown the preferred form of our invention, as now known to us, it will be under- Y claim and desire to secure by Letters Patent is: 70

p 1. A drilling safety joint comprising a pair of tubular members disposed in longitudinal alignment with each other, an intermediate section j splined for limited longitudinal movement within one of the tubular sections and having a tubular members disposed in longitudinal alignment with each other, an intermediate 'section splined for limited longitudinal movement with- Y in one of the tubular sections and having a threaded/connection with the other `of said tu-I bular sections, yieldable means maintaining the splined portion of theintermediate section in its outermost position, and means carried at contiguous ends of thetubular sections for interlocking said sections to produce rotation o! the sections in unison and whereby relative longigagement, and whereby subsequent counter-- tudinal movement of the sections against the action of the yielding meanswill permit the sec-L tions to be released from their interlocking enrotation of the two sections will cause the threaded connection between the intermediate section and the tubular section .to be unscrewed and the.

tubular sections of the safety jointcompletely separated. Y A 3. A drilling safety joint comprising a pairof tubular sections disposed lin longitudinal alignment, hook-shaped locking means carried by one of said sections, complementary locking membersv carried bythe other of said sections whereby the 'i sections 4may be locked against rotation with rel iaton, to each other in'either direction, and 40 .whereby longitudinal movement and subsequent A l stomacor threaded connection w'itiithe other of said tuburotation of the sections with relation to each othe will bring the hooks and lock means into yout of their interlocking engagement. Y 4. A drilling safety joint comprising a pair of tubular sections disposedin longitudinal align- 5" ment, hook-shaped lockingmeans carried by one of said sections, complementary locking members carried by the otherA of said'sections whereby the sections may be locked against rotation with relation to each other in either direction, and 104 Awhereby longitudinal movement and subsequent rotation of the sections with relation to each other will bring the hooks and lock means into and out of their interlocking engagement, and yieldable means acting to maintain said interlocking me'mbers in their engaged positions.

5. A drilling safety joint comprising a' pair of tubular .sections disposed in longitudinal alignment, hook-shaped locking means carried by one of said sections, complementary locking mem- 20' bers'carried by the other ot said sections whereby the sections maybe locked against rotation with relation to each other in either direction, and

whereby longitudinal novement and subsequent rotation of the sections with relation to each .other will bring the hooks and lock means into and out of their interlocking engagement-an intermediate section splinedto the upper tubular section for limited longitudinal movement relative thereto and having a threaded connection with the lower tubular section, and means between the intermediate section and the lower tubular section for positively locking the sections against relative movement in a clockwise direction and for permitting the sections to be .directly un- 35 Vscrewed by colmterclockwise rotation when the hook locking means has been released.

ERWIN BURNS. HARRY P, 

